package cn.regexp.util;

import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;

/**
 * sha1 加密工具类
 */
public class Sha1Util {
	public static String getSha1(String str) {
		// 参数校验
		if (str == null || str.length() == 0) {
			return null;
		}
		// 十六进制数字
		char[] hexDigits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
				'a', 'b', 'c', 'd', 'e', 'f' };
 
		try {
			MessageDigest mdTemp = MessageDigest.getInstance("SHA1");
			mdTemp.update(str.getBytes(StandardCharsets.UTF_8));
 
			byte[] md = mdTemp.digest();
			int j = md.length;
			char[] buf = new char[j * 2];
			int k = 0;
			for (byte byte0 : md) {
				buf[k++] = hexDigits[byte0 >>> 4 & 0xf];
				buf[k++] = hexDigits[byte0 & 0xf];
			}
			return new String(buf);
		} catch (Exception e) {
			return null;
		}
	}
}